Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 216 insertions, 0 deletions

diff --git a/target/i386/tcg/sysemu/seg_helper.c b/target/i386/tcg/sysemu/seg_helper.c
new file mode 100644
index 000000000..bf3444c26
--- /dev/null
+++ b/target/i386/tcg/sysemu/seg_helper.c
@@ -0,0 +1,216 @@
+/*
+ *  x86 segmentation related helpers: (sysemu-only code)
+ *  TSS, interrupts, system calls, jumps and call/task gates, descriptors
+ *
+ *  Copyright (c) 2003 Fabrice Bellard
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "exec/helper-proto.h"
+#include "exec/cpu_ldst.h"
+#include "tcg/helper-tcg.h"
+#include "../seg_helper.h"
+
+#ifdef TARGET_X86_64
+void helper_syscall(CPUX86State *env, int next_eip_addend)
+{
+    int selector;
+
+    if (!(env->efer & MSR_EFER_SCE)) {
+        raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC());
+    }
+    selector = (env->star >> 32) & 0xffff;
+    if (env->hflags & HF_LMA_MASK) {
+        int code64;
+
+        env->regs[R_ECX] = env->eip + next_eip_addend;
+        env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
+
+        code64 = env->hflags & HF_CS64_MASK;
+
+        env->eflags &= ~(env->fmask | RF_MASK);
+        cpu_load_eflags(env, env->eflags, 0);
+        cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
+                           0, 0xffffffff,
+                               DESC_G_MASK | DESC_P_MASK |
+                               DESC_S_MASK |
+                               DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK |
+                               DESC_L_MASK);
+        cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
+                               0, 0xffffffff,
+                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
+                               DESC_S_MASK |
+                               DESC_W_MASK | DESC_A_MASK);
+        if (code64) {
+            env->eip = env->lstar;
+        } else {
+            env->eip = env->cstar;
+        }
+    } else {
+        env->regs[R_ECX] = (uint32_t)(env->eip + next_eip_addend);
+
+        env->eflags &= ~(IF_MASK | RF_MASK | VM_MASK);
+        cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
+                           0, 0xffffffff,
+                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
+                               DESC_S_MASK |
+                               DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK);
+        cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
+                               0, 0xffffffff,
+                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
+                               DESC_S_MASK |
+                               DESC_W_MASK | DESC_A_MASK);
+        env->eip = (uint32_t)env->star;
+    }
+}
+#endif /* TARGET_X86_64 */
+
+void handle_even_inj(CPUX86State *env, int intno, int is_int,
+                     int error_code, int is_hw, int rm)
+{
+    CPUState *cs = env_cpu(env);
+    uint32_t event_inj = x86_ldl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
+                                                          control.event_inj));
+
+    if (!(event_inj & SVM_EVTINJ_VALID)) {
+        int type;
+
+        if (is_int) {
+            type = SVM_EVTINJ_TYPE_SOFT;
+        } else {
+            type = SVM_EVTINJ_TYPE_EXEPT;
+        }
+        event_inj = intno | type | SVM_EVTINJ_VALID;
+        if (!rm && exception_has_error_code(intno)) {
+            event_inj |= SVM_EVTINJ_VALID_ERR;
+            x86_stl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
+                                             control.event_inj_err),
+                     error_code);
+        }
+        x86_stl_phys(cs,
+                 env->vm_vmcb + offsetof(struct vmcb, control.event_inj),
+                 event_inj);
+    }
+}
+
+void x86_cpu_do_interrupt(CPUState *cs)
+{
+    X86CPU *cpu = X86_CPU(cs);
+    CPUX86State *env = &cpu->env;
+
+    if (cs->exception_index == EXCP_VMEXIT) {
+        assert(env->old_exception == -1);
+        do_vmexit(env);
+    } else {
+        do_interrupt_all(cpu, cs->exception_index,
+                         env->exception_is_int,
+                         env->error_code,
+                         env->exception_next_eip, 0);
+        /* successfully delivered */
+        env->old_exception = -1;
+    }
+}
+
+bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
+{
+    X86CPU *cpu = X86_CPU(cs);
+    CPUX86State *env = &cpu->env;
+    int intno;
+
+    interrupt_request = x86_cpu_pending_interrupt(cs, interrupt_request);
+    if (!interrupt_request) {
+        return false;
+    }
+
+    /* Don't process multiple interrupt requests in a single call.
+     * This is required to make icount-driven execution deterministic.
+     */
+    switch (interrupt_request) {
+    case CPU_INTERRUPT_POLL:
+        cs->interrupt_request &= ~CPU_INTERRUPT_POLL;
+        apic_poll_irq(cpu->apic_state);
+        break;
+    case CPU_INTERRUPT_SIPI:
+        do_cpu_sipi(cpu);
+        break;
+    case CPU_INTERRUPT_SMI:
+        cpu_svm_check_intercept_param(env, SVM_EXIT_SMI, 0, 0);
+        cs->interrupt_request &= ~CPU_INTERRUPT_SMI;
+        do_smm_enter(cpu);
+        break;
+    case CPU_INTERRUPT_NMI:
+        cpu_svm_check_intercept_param(env, SVM_EXIT_NMI, 0, 0);
+        cs->interrupt_request &= ~CPU_INTERRUPT_NMI;
+        env->hflags2 |= HF2_NMI_MASK;
+        do_interrupt_x86_hardirq(env, EXCP02_NMI, 1);
+        break;
+    case CPU_INTERRUPT_MCE:
+        cs->interrupt_request &= ~CPU_INTERRUPT_MCE;
+        do_interrupt_x86_hardirq(env, EXCP12_MCHK, 0);
+        break;
+    case CPU_INTERRUPT_HARD:
+        cpu_svm_check_intercept_param(env, SVM_EXIT_INTR, 0, 0);
+        cs->interrupt_request &= ~(CPU_INTERRUPT_HARD |
+                                   CPU_INTERRUPT_VIRQ);
+        intno = cpu_get_pic_interrupt(env);
+        qemu_log_mask(CPU_LOG_TB_IN_ASM,
+                      "Servicing hardware INT=0x%02x\n", intno);
+        do_interrupt_x86_hardirq(env, intno, 1);
+        break;
+    case CPU_INTERRUPT_VIRQ:
+        cpu_svm_check_intercept_param(env, SVM_EXIT_VINTR, 0, 0);
+        intno = x86_ldl_phys(cs, env->vm_vmcb
+                             + offsetof(struct vmcb, control.int_vector));
+        qemu_log_mask(CPU_LOG_TB_IN_ASM,
+                      "Servicing virtual hardware INT=0x%02x\n", intno);
+        do_interrupt_x86_hardirq(env, intno, 1);
+        cs->interrupt_request &= ~CPU_INTERRUPT_VIRQ;
+        env->int_ctl &= ~V_IRQ_MASK;
+        break;
+    }
+
+    /* Ensure that no TB jump will be modified as the program flow was changed.  */
+    return true;
+}
+
+/* check if Port I/O is allowed in TSS */
+void helper_check_io(CPUX86State *env, uint32_t addr, uint32_t size)
+{
+    uintptr_t retaddr = GETPC();
+    uint32_t io_offset, val, mask;
+
+    /* TSS must be a valid 32 bit one */
+    if (!(env->tr.flags & DESC_P_MASK) ||
+        ((env->tr.flags >> DESC_TYPE_SHIFT) & 0xf) != 9 ||
+        env->tr.limit < 103) {
+        goto fail;
+    }
+    io_offset = cpu_lduw_kernel_ra(env, env->tr.base + 0x66, retaddr);
+    io_offset += (addr >> 3);
+    /* Note: the check needs two bytes */
+    if ((io_offset + 1) > env->tr.limit) {
+        goto fail;
+    }
+    val = cpu_lduw_kernel_ra(env, env->tr.base + io_offset, retaddr);
+    val >>= (addr & 7);
+    mask = (1 << size) - 1;
+    /* all bits must be zero to allow the I/O */
+    if ((val & mask) != 0) {
+    fail:
+        raise_exception_err_ra(env, EXCP0D_GPF, 0, retaddr);
+    }
+}